SAT-WIND: Winds from satellites for offshore and coastal wind energy mapping and wind-indexing

Applicability of satellite wind maps derived from passive microwave, altimeter, scatterometer and imaging SAR technologies as tools for wind resources and wind-indexing.



Winds from satellites for offshore and coastal wind energy mapping and wind-indexing.



The SAT-WIND project runs in years 2004 and 2006 with funding from the Danish Technical Research Council (STVF) at the Danish Research Agency.



Background

Planning wind farms offshore are generally based on little knowledge of the wind speeds. It is due to the limited amount of offshore meteorological observations worldwide. This again has put a severe limitation to verification on offshore wind model results. Current practices on the modeling offshore winds therefore introduce significant uncertainties. For wind farm owners the wind power production may deviate from the prospected output and wind-indexing becomes a necessary tool in surveying on-going wind farm projects as well as in recommendations for new offshore wind farm initiatives.



Until now offshore wind observations from satellites have not been used for offshore wind energy purposes even though wind maps from various technologies such as passive microwave, altimeter, scatterometer and imaging synthetic aperture radar (SAR) are available for more than one decade. The two major reasons for not using satellite winds within offshore wind energy are



satellite wind mapping accuracy (absolute precision, mapping frequency, spatial scale)

technological methodologies to tranfer satellite data to wind energy tools

For selection of the ‘right spots’ for planning offshore and coastal wind farms, just the relative offshore wind speeds would be of importance. In (pre)-feasibility studies where a large region typically is under investigation, a lower absolute accuracy on the wind estimate may be acceptable. The spatial wind variations mapped from satellites may be used for pointing out where to put up the relatively expensive offshore met-masts. In regard to wind-indexing continuous and frequent wind observations are necessary. This now can be provided by satellite wind observations.



Goal

The goal of the project is to verify the applicability of satellite wind maps derived from passive microwave, altimeter, scatterometer and imaging SAR technologies for wind energy tools for wind resources and wind-indexing.



Earth Observation data and study site

The satellite images under study are passive microwave data from SSM/I, scatterometer data from ERS-2 AMI Scat and Quikscat, altimeter data from TOPEX/Poseidon, and imaging synthetic aperture radar (SAR) data from ERS-2 SAR and ENVISAT ASAR covering the North Sea.



Participants



Risø National Laboratory, Wind Energy Department Charlotte Bay Hasager (coordinator), Rebecca Barthelmie, Morten Nielsen, Merete Christiansen, Jørgen Højstrup, Poul Astrup,

Energi- og Miljø data Per Nielsen

Elsam Engineering: Paul Sørensen



Acknowledgements

Satellite scenes are kindly granted at research cost through the ESA EO-1356 project. Charlotte Bay Hasager is the PI